Ficoll/Hypaque and/or glass wool separated peripheral blood lymphocytes are washed three times and resuspended in the 1-2 x 10 to the 7th power cell/cc range in RPMI 1640 plus 33% pooled human AB serum. These cells are chilled to 4 degrees and dilute cold DMSO added slowly to a final concentration of 7.5% DMSO. This material is transferred to 2cc polyethylene vials in lcc alliquots and frozen at a controlled ratio of 1 degree C/minute, and then stored in the vapor phase of a liquid nitrogen freezer. Recovery of the frozen cells is accomplished by rapid warming in a 37-40 degrees water bath and immediately the cryoprotectant is diluted with a 10x volume of room temperature medium (RPMI 1640) containing 10% human AB serum. The cells are then washed twice more at a centrifuge speed of not over 300g, counted and resuspended for assay. Variations of the above procedure using single cell suspension and minced tissue will be evaluated for function and viability.